Count Even and Odd numbers in an Array

“Count Even and Odd numbers in an Array” is an elementary problem of array data structure for beginners. Here, we are given an array of size ‘n’ and our task is to count the number of even elements and number of odd elements of an array.

Example:

INPUT:
Enter the size of array: 5
Array[5] = {1, 2, 3, 4, 5}
OUTPUT:
Number of odd elements: 3
Number of even elements: 2

The steps required to count Even and Odd numbers in an Array are as follows:

1. Set odd_count  = 0 and even_count = 0.
2. Start scanning the array element. For each array element, check if it even or odd.
3. If the array element is even number then, increment even_count by: even_count = even_count + 1.
4. If the array element is odd number then, increment odd_count by: odd_count = odd_count + 1.
5. Print the odd_count and even_count

C++ Program to Count Even and Odd numbers in an Array are as follows:

/* C++ Program to Count Even and Odd numbers in an Array */  
#include<bits/stdc++.h>  
using namespace std;  
int main()  
{  
    int n;  
      
    /* Scanning size of the array */  
    cout<<"Enter the number of array elements: ";  
    cin>>n;  
      
    /* Creating an Array */  
    int arr[n];  
      
    /* Scanning the array elements */  
    cout<<"\nEnter the array elements: ";  
    for(int i = 0; i < n; i++)  
    cin>>arr[i];  
      
    int odd_count = 0;  
    int even_count = 0;  
      
    /* Count the even and odd elements */  
    for(int i = 0; i < n; i++)  
    {  
        if(arr[i] % 2 == 0)  
        even_count = even_count + 1;  
        else if(arr[i] % 2 != 0)  
        odd_count = odd_count + 1;  
    }  
      
    /* Printing the result */  
    cout<<"\nThe number of odd elements in an array are: "<<odd_count<<"\n";  
    cout<<"The number of even elements in an array are: "<<even_count<<"\n";  
}  

OUTPUT:
 
Enter the number of array elements: 5
Enter the array elements: 1 2 3 4 5
The number of odd elements in an array are: 3
The number of even elements in an array are: 2
 Time Complexity:
O(n), where n is the size of the array

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